Lifting jack



Jan. 17, 1928. 1,656,382

'R. c. MOCOLLEY LIFTING JACK Filed April 26, 1926 ESE IHVEHTbR, Faber Z C. M (o/ /6 J mrhm,

fitterneds.

Patented Jan. 17, 1928.

UNITED *STATES ROBERT C. McCOLLEY, OF INDIANAPOLIS, INDIANA.

LIFTING JACK.

Application filed. April 26, 1926. Serial No. 104,526.

This invention comprises a ack which has for its principal object the means for preventing side thrust from interfering with the smooth action of the jack should the load be carried at an angle to the axis of the jack, and reference is had to the accompanying drawing, in which-- a 1 Fig. 1, is a side elevation of a jack carried on cribbing;

Fig. 2, a vertical section through the jack; and v Fig. 3, a transverse section takenv on the line 33 in Fig. 2.

Like characters of reference indicate like parts throughout the several views.

The jack here shown is of the type com monly used in house moving, or in such work where the load is raised beyond the liftof the jack whereby cribbing is employed to carry the ack up to obtain the desired elevation.

The jack is comprised of the central screw-threaded shaft 10 which carries the bearing plate 11 screw-threadedly thereon. It will be noted that this plate'll has a smooth undersurface and has no depending lugs or brackets to prevent turning of the plate under heavy loads.

A head 12 is mounted on the top of the shaft 10 and is preferably cast integrally with the shaft. The head 12 is provided with the usual holes 13 to receive bars or handles (not shown) in the usual manner as a means of revolving the shaft 10 in the bearing plate 11.

The upper face of the head is turned to form a shoulder to receive a ball-bearing race 12% thereon, and a guide 15 projects centrally thereabove to receive thereover the headcap 16. The laalbbearings 17 are carried in the annular channel of the race 14 and a similar channel is formed in the under face of'the headcap 16 to complete the bearing whereby the head-cap is supported vertically by the balls 17 a I The uppermost part of the headcap 16 is formed into a ball-shaped knob which is re ceived in the socket of the cap-plate 18. A screw 19 is slidingly passed through the head-cap 16 and screw-threadedly engaged in the head 12 as ameans of retaining the cap 16 in place. The cap-plate 18 is loosely carried on the knob of the head-cap 16.

In practice, it is rarely the case that the upper face of the cap-plate 18, which is the surface that goes against the object to be lifted, can be held in a position parallel to that of the under surface of the bearing plate 11, and the result is usually the case that the cap-plate 18, being carried on the jack by a ball and socket joint, is at an angle to the axis of the jack, and by reason of the ball and socket joint construction in combination with the ball-bearing construction within the head, such angular thrust on the jack sets up no undue stress that might otherwise interfere with the operation of the ack.

It is to be noted that the head-cap 16 has a lip 21 extending down over the opening into the ball-bearing so as to exclude dirt.

\Vhilethe bearing plate 11 is here shown as having the smooth under surface, it will i be noted that it has reinforcing ribs 20, and under some conditions, it may be advisable, to reverse the plate 11 on the shaft 10 whereby the flat surface is above and the ribs 20 extend below for the purpose of allowing the ribs 20 to be gripped between the blocks of the cribbing and as a means of decreasing the effective height of the plate so that the jacks may be used in a closer place than one in which the plate is left as shown.

I claim:

The conibiiultion of a screw shality a base 1.

plate screw- -threadedly carried on the shaft; a head fixed to the shaft, saidhead having an annular seat thereon; a removable ball race on said annular seat; a pilot finger extending centrally through said race from the head having a reduced end forming a shoulder; a hemis 'iherically shaped cap rotatablv positioned over said race by said pilot linger extending into a hole in the cap, said cap being partly seated on the shoulder having an annular ball race formed in its under side to conform to said first race whereby a plurality of ball bearings may be carried in the two said races to separate the cap from. the head; a ball shaped knob on the cap; a screw slidingly passed through said ball shaped knob cap and screw-threadedly engaged in said pilot finger as a means of retaining said cap on said head; and an annular lip projecting from said cap down over the opening between said cap and said head as occassioned by said ball bearings;

and a Cap plate having a socket to receive a minor portion at a time of said ball tip to secure a universal adjustment of the cap 10 plate.

In testimony whereof I afiix my'signat-ure.

ROBERT C. MoCOLLEY 

